ERROR : Error: Could not find or load main class org.apache.ambari.server.DBConnectionVerification

[#1]

Description - When we start the oozie/hive from ambari it checks the connectivity with db first before starting using below command

/usr/java/jdk64-1.7.0_79/bin/java -cp /usr/lib/ambari-agent/DBConnectionVerification.jar:/usr/hdp/current/oozie-server/libext/ojdbc.jar org.apache.ambari.server.DBConnectionVerification '<<DB URL>>
Error - Ambari was not able to load the class due to permission issue on the jar file
   Current Permission —>  -rw-r----- 1 root root 1931 Jan 29 01:02 /usr/lib/ambari-agent/DBConnectionVerification.jar(640)
  Required Permission —> -rw-r--r-- 1 root root 1931 Jan 29 01:02 /usr/lib/ambari-agent/DBConnectionVerification.jar(644)

Change the permission from 640 to 644.

[#2]

@Ritesh Chaman this is an article not a question. Look at the last message in your log, change permission to 644.